Trisomy of 1q in preleukaemia with progression to acute leukaemia

Partial trisomy 1q. A nonrandom primary chromosomal abnormality in myelodysplastic syndromes?

Cytogenetic and clinical data of 11 patients with de novo myelodysplastic syndromes and partial or total trisomy of the long arm of chromosome 1 are presented. In eight of these patients trisomy 1q was the sole karyotypic change and therefore can be classified as a primary chromosome anomaly. A remarkably young median age of 36.5 years was noticed in this patient group.

Cytogenetic findings in siblings with a myelodysplastic syndrome

A brother and sister, both in their third decade, presented 6 months apart with severe pancytopenia. Bone marrow examination demonstrated morphologic changes, characteristic of the myelodysplastic syndromes, subtype refractory anemia with excess of blasts; cytogenetic studies revealed complex but different karyotypic abnormalities in both siblings. No history of exposure to mutagenic agents was obtained; there was no evidence of congenital anomalies in the family. Both siblings died within 18 months of diagnosis from complications related to their disease. This report describes the clinical course and discusses the cytogenetic findings for both siblings.

11q-chromosome is associated with abnormal iron stores in myelodysplastic syndromes

Nine cases of myelodysplastic syndrome with a deletion of the long arm of chromosome #11 (11q-) showed ringed sideroblasts, and three of which had an acquired sideroblastic anemia according to the criteria of the FAB classification. In contrast, among four cases of myelodysplastic syndromes with translocation of extra material to the long arm of chromosome #11 (11q+), only one showed bone marrow sideroblasts. These results strongly indicate that an 11q- chromosome is a marker of iron overload in myelodysplastic syndromes. Within the cases of 11q- associated with sideroblastosis, two cytogenetically different anomalies (i.e., terminal or interstitial deletions) were delineated.

An identical translocation between chromosome 1 and 15 in two patients with myelodysplastic syndromes

An identical translocation between the long arm of chromosome no. 1 and the short arm of chromosome no. 15 was found in two unrelated patients with refractory anaemia type I, according to the FAB classification of myelodysplastic syndromes. In the first patient the typical translocation was associated with anomalies commonly found in preleukaemic states, i.e. a 5q- and a 20q- chromosome. Furthermore, in both patients the long arm of chromosome no. 1 was trisomic. Cytogenetic follow-up in the second patient demonstrated a proliferative advantage of the cells bearing a t(1;15) translocation over the cells with trisomy 8 as well as over normal cells. This karyotypic evolution, however, was not accompanied by a transformation of the haematological disorder into acute leukaemia.

Major karyotype aberrations, including t(3;12), in a patient with myelodysplastic syndrome

Cytogenetic analysis of bone marrow cells was performed twice on a patient with myelodysplastic syndrome, specifically, refractory anemia with excess blasts. The patient had a progressive course, with transformation toward acute leukemia and death within 3 months. Chromosome analysis showed major karyotype abnormalities, including dir dup (1p), t(3;12), and a unique breakage of a #15 resulting in t(15;18) and dic(15;21). Involvement of #3 and #12 in a translocation has been recently reported, and a comparison with these cases is made with a discussion of the significance.

Translocation 1;7 in dyshematopoiesis: possibly induced with a nonrandom geographic distribution

Eight patients with various hematologic disorders had an identical chromosomal aberration in their bone marrow or unstimulated peripheral blood, a translocation t(1;7) interpreted as t(1;7)(p11;p11). The translocation chromosome replaced one normal chromosome #7; therefore, the karyotype of the abnormal cells was trisomic for 1q and monosomic for 7q. Including four cases from the literature, a total of 12 patients (4 women, 8 men) with this translocation are known at the moment. The translocation does not seem to be associated with a specific disorder, but almost all patients had a preleukemic syndrome during some stage of their disease. It is very remarkable that 11 of the 12 patients lived in the Netherlands, and 7 patients had a history of iatrogenic exposure to alkylating agents or irradiation; one patient was a radiation worker and another one had a history of toxic exposure to chloramphenicol. It is suggested, therefore, that the t(1;7) is a possibly induced chromosomal aberration with a clearly nonrandom geographic distribution.

The relationship between growth in agar, karyotype and prognosis in acute leukaemia

The growth pattern in agar culture and the karyotype of bone marrow cells were studied in 79 patients with untreated acute non-lymphocytic leukaemia (ANLL). Results were divided into the following groups: (A) colony and cluster formation; (B) growth of less than 600 small clusters per 10(5) cells; (C) growth of more than 600 small clusters; (D) no growth in agar. Cytogenetically, the patients were divided into 3 categories: NN, normal metaphases only; AN, both abnormal and normal metaphases and AA, abnormal metaphases only. An association was seen between growth pattern and karyotype: the majority of NN patients (33/37) belonged to group (A + B) while in group (C + D) 20/24 patients were AN or AA. 37 patients were prognostically evaluable. The growth pattern in agar but not the cytogenetic pattern had prognostic implications. 25 patients with acute lymphocytic leukaemia (ALL) were also studied at diagnosis. Different growth patterns in agar had no impact on prognosis. No relationship was detected between growth pattern and karyotype in ALL.

Anomalies of the long arm of chromosome 11 in human myelo- and lymphoproliferative disorders. I. Acute nonlymphocytic leukemia

In a series of 365 consecutive ANLL cases of which 45.1% had abnormal karyotypes, 13 cases were detected with a structural abnormality of the long arm of chromosome 11. Besides one isochromosome 11q, there were six deletions and six translocations. Of these 12 patients, seven had acute monocytic leukemia (FAB-type M5), two had an M4, two had an M2, and one case of secondary leukemia had an M3-like disorder. Similar results with regard to the type of leukemia were obtained upon analysis of 41 cases of ANLL with an 11q anomaly described in the literature. This study confirms that a high proportion of acute monocytic leukemias and a lesser proportion of acute myelomonocytic leukemias are characterized by an 11q anomaly, mostly involving bands q22 and/or q23. Acute monocytic leukemia with an 11q structural anomaly appears to have a poor prognosis.

Complete or partial trisomy for the long arm of chromosome 1 in patients with various hematologic malignancies

This study contains data obtained from a cytogenetic investigation of six patients with acute and chronic leukaemia. The karyotypes of bone marrow or blood cells of these patients showed a partial or complete trisomy for the long arm of chromosome 1. Three observations revealed a pronounced resistance of cell clones with 1q+ towards cytostatic therapy, and a comparatively short life span of patients after detection of 1q+. The importance of these changes for the role of some chromosomes and chromosome loci in leukaemogenesis is discussed.

Diagnostic and prognostic significance of chromosome abnormalities in marrow and mitogen response of lymphocytes of acute nonlymphocytic leukemia

Chromosomes of bone marrow from 28 patients with acute nonlymphocytic leukemia (ANLL) (26 with AML, 2 with AMMoL), 19 of whom had chromosome abnormalities, were studied; 11 cases exhibited previously unreported karyotypic abnormalities. The marrows of two cases had 8-21 translocations associated with an iso-X chromosome in the female patient and with 9q13- and a missing Y in the male patient. Usually, AML patients with a 8-21 translocation have been considered to have a good prognosis; however, our cases had rather short survival times. Therefore, the prognosis of AML with an 8-21 translocation but associated with other abnormalities is still not clear. Centromere spreading (CS), which was originally reported in marrow cells of megaloblastic anemia (B12 and folic acid deficiency), was detected in leukemic cells, disappeared during remission, and reappeared on relapse. These findings suggest that CS may be a new type of abnormality in AML. In two patients with atypical hypoplastic anemia and hemolytic anemia, chromosome abnormalities were detected at the anemic stage. One case with CS was associated with atypical hypoplastic anemia and developed AML after 1 year; the other with 48,XY,+i(1q),+3,/12 and -14 had hemolytic anemia and developed AMMoL 3 weeks later. Interestingly, identical clones were detected both before and after the clinical diagnosis of leukemia. These cases strongly support the concept that some chromosome abnormalities precede the clinical manifestations of leukemia. The present study also revealed that lymphocytes in ANLL respond poorly to PHA in the presence of high numbers of blasts but do respond well to mitogens during remission. Therefore, the response of lymphocytes to PHA may serve as one criterion for determining remission.

Cytogenetic studies on four cases of non-endemic Burkitt lymphoma

Cytogenetic studies carried out on four children with non-endemic Burkitt lymphoma showed: 1) Two with the typical translocation t(8;14)(q24;q23); 2) one with a variant t(2;8)(p11;q24); and 3) one with apparently normal chromosomes 8 and 14. Additional chromosomal variation was present in all four patients. Two were shown to have a duplication of part of the long arm of chromosome 1 (1q23 leads to 1q32 and 1q23 leads to 1q42). Epstein Barr virus studies on two patients showed that one was positive and the other negative. A comparison of these results with other non-endemic cases in the literature has been made revealing a wider range of chromosomal variation than has been hitherto reported for endemic cases. The finding that chromosome 8 is also involved in the variant translocations in Burkitt lymphoma suggests that its changes may contribute more to the tumour development than the than the 14q+.

Break points in chromosome #1 abnormalities of 218 human neoplasms

A survey of 343 break points that lead to chromosome #1 abnormalities in 218 human neoplasms showed that 49.9% were located in or immediately adjacent to the centromeric heterochromatin. Amongst rearrangements with breaks in bands p 12-q21 were 27 isochromosomes, 22 translocations of the long arm, and four translocations of the short arm to the heterochromatic regions of other chromosomes, and 35 deletions resulting in chromosomes consisting mainly or solely of one arm. Deletions following breakage at various sites in the short arm of chromosome #1 are frequent in malignancies and are quite often found in cells that are trisomic for the long arm. It is suggested that fragility of chromosomes generated as a result of early events in carcinogenesis may be one source of chromosome rearrangements, including those of chromosome #1, on which selection can operate and give rise to progressively more malignant clones.

All patients with acute nonlymphocytic leukemia may have a chromosomal defect

Previous studies of banded marrow chromosomes suggest that half the patients with acute nonlymphocytic leukemia (ANLL) have normal karyotypes. To determine whether high-resolution chromosome analysis could detect additional abnormalities, we studied marrow from 26 patients with ANLL, using methotrexate cell synchronization as well as a direct technique. In 24 patients, including 18 who were untreated, adequate mitoses were obtained. All demonstrated clonal chromosomal abnormalities, which involved a balanced translocation in 11 cases, a complete or partial monosomy in 10, and a trisomy in six. Previously reported recurring defects in ANLL were identified, including t(15;17) in two cases, -7 in two cases, and +8 in three cases. In addition, a new specific abnormality involving band 11q23 was noted in one patient with acute monocytic leukemia and in two with myelomonocytic leukemia. Our results suggest that most, if not all, patients with ANLL have chromosomal changes, and that our new technique may allow more precise identification of subtypes of ANLL with characteristic clinical and hematologic features.

Human tumour karyology: marked analytic improvement by short-term agar culture

A simple method has been developed which facilitates the detailed cytogenetic analysis of proliferating tumour cells within clusters and colonies arising from clonogenic tumour stem cells in biopsy samples of human cancers. The method uses a simple agar cloning technique for human tumours, which provides marked enhancement in the number of cases with observable mitotic activity and the number of mitotic figures available for detailed karyotypic assessment. The frequency of mitotic figures in cluster and colony samples is much greater than is attainable with standard chromosomal techniques. This novel approach should prove to be a powerful tool for the study of human tumour karyology.

Chromosome 1 abnormalities in relapse and terminal stages in childhood leukemia

Seven of 114 children with leukemia were shown to have abnormalities of chromosome 1. These included trisomy of parts of chromosome 1 as well as translocations of chromosome 1 to other chromosomes. The abnormalities were found during a relapse or terminal stage, after which the patient was refractory to therapy in all cases.